IT security watchers have warned of a Trojan spammed out in large quantities to email users around the world.
When opened the Word document attempts to install another Trojan horse, called Kuku-A, onto the user's hard drive, which can lead to hackers gaining access to innocent users' PCs.
The spam comes with a variety of subject lines including 'worth to see', 'prices', and 'Hello'. It is currently the number one reported malware, according to Sophos' global network of monitoring stations.
Attached to the email is a zip file (variously called 'prices.zip',
'apple_prices.zip' or 'sony_prices.zip') containing a malicious Word document
It is believed that the author behind the malware is also responsible for the Sality worms which log keystrokes to steal information from computer users.
"People may be curious as to why they have been sent the email and open the attached file, but doing so would be a big mistake," said Graham Cluley, senior technology consultant at Sophos.
"This malware is being aggressively spammed out in an attempt to break into innocent users' Windows computers.
"The Trojan will try and download further code from the internet which could allow hackers to gain access to the computer in order to spy, steal and cause havoc."
Dust storm on Titan only the third Solar System body where such storms have been observed
New technique could enable quantum computers to scale-up to millions of qubits
Systrom and Krieger taking time off "to explore our curiosity and creativity"
Comcast's £29.7bn winning bid more than twice the £13.7bn Rupert Murdoch valued Sky at just eight years ago